In known reciprocating motor compressors, the refrigerant gas, which arrives from a vaporizer in the surrounding shell, passes through a muffler and into a suction chamber which is formed in the head, and from there, through a valve plate it is sucked into the cylinder.
From the cylinder the compressed gas passes through a discharge port in the valve plate and arrives in a delivery chamber, also formed in the head, and from there the gas is sent to a condenser.
In compressing the gas, work is required, thus there is generation of heat which is partially transmitted to the head by the gas in the delivery chamber. Since the delivery chamber is contiguous to the suction chamber, this chamber also gets hot, thus the gas passing through the suction muffler absorbs heat before entering the cylinder. According to known physical laws, the heating of a gas causes an increase of volume, thus the refrigerant gas, if it absorbs heat in the suction chamber, increases its volume and, as a consequence, the density of gas sucked into the cylinder is lower than the density of gas that would be sucked into the cylinder if the gas were at a lower temperature.
The foregoing causes a smaller amount of inlet refrigerant gas to be introduced into the refrigerant apparatus in the delivery phase and this causes a loss of efficiency of the refrigerating cycle. In order to overcome this drawback in the present invention the suction chamber in the head has been eliminated and the muffler is fixed to be in direct communication with a suction hole formed in the valve plate. The vibrations of the compressor causes, after some time, a defective coupling of the muffler with the suction hole. Thus a certain quantity of gas, instead of being sucked into the cylinder, disperses inside the compressor shell causing decreased efficiency of the refrigerating apparatus as a smaller quantity of refrigerant gas is compressed at every cycle.
In another solution for the above problem the suction muffler, which is positioned on the valve plate, is kept in position by a screw into the cylinder.
This solution does not assure a perfect coupling between the suction hole of the valve plate and the muffler. There is a dispersion of gas and thus lower efficiency. Another drawback of this solution is an increase in noise as the defective adhesion of the muffler end with the valve plate produces noise generated by the gas flow and a loss of sound-proofing of the circuit.
It is the purpose of the present invention to overcome the above-described drawbacks.